1. Field of the Invention
The present invention relates to an improved driven vehicle of an automatic transport system, which vehicle is movable unmanned along a predetermined path. Such vehicles are known specifically for the automatic transport of workpieces in factory halls.
2. Description of the Prior Art
Such vehicles move also around halls of factories or factory buildings and generally along predetermined paths which are marked usually yellow and without any additional barriers such that in case of a collision the vehicles must brake to a stop within the safety brackets which are mounted in the direction of vehicle movement in a freely supported condition or are suspended by wires. For structural reasons these stationarily mounted safety brackets cannot exceed a predetermined length and because these brackets offer extremely insufficient safety at the inner side of curves of the path, speeds of a higher magnitude, for instance, speeds higher than 60 m/min, are impossible due to safety considerations. If the speed is to be increased in order to improve the transporting capacity such as, for instance, in freely open areas having long traveling distances, the prior art as hitherto known allows such in closed off or confined, respectively, areas only, which in practice limits the application of such transport vehicles to a great extent.
The British patent specification GB-PS No. 2 014 773 discloses an exclusively passive operating safety stopping apparatus which cooperates with insertable gripping members of a forklift. If a force acts upon the gripping members, the gripping members will be inserted, pushed inwards (against a biassing spring force) and accordingly the braking operation is triggered. Quite obviously the solution described is not suitable for protecting persons against injury in case of a collision. The same proves true for the design disclosed in the British patent specification GB-PS No. 1 430 406. The solution disclosed is a telescoping arm which projects by a larger or smaller distance in accordance with the prevailing speed. And when a force acts upon this telescoping arm, the braking is triggered. A pushing in of the arm applies thereby a moment onto a driving drum. If this moment exceeds a predetermined value, the triggering is initiated. This system comprises also no retracting mechanism which is triggered upon collisions.